Furnace lining



Sept; G. D. EVANS 1,775,161,

FURNACE LINING Filed March 14, 1928 FIG. I.

F|6.2. FIGB.

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Patented Sept. 9, 1930 UNITED STATES PATENT OFFICE (Sui-33GB DAVID EVANS, OF BAIlZe'lIMIOBJl, MARYLAND, ABSIGNOR To AMERICAN SHELT- ING- AND REFINING COMPANY, OF NEW YORK, N. Y., A OORIOBATION OF NEW JERSEY scanner: LINING Application filed Harch' 14, 1928. Serial No. 261,497.

This invention relates to furnaces, and more particularly to furnace linings and a method of forming the same.

This invention may be applied specifically 6 to refining furnaces; for example, furnaces used in the refining of copper. Such fur- "naces are commonly constructed with their inner walls of magnesitebrick,whichbecomes worn during use as the result of the chemical 10 action of the charge and of the mechanical forces resulting from the great temperature range to which furnace of this type is subjected. The in i'ention provides a lining which may be applied to the face of the magnesite brick and will serve as a protection therefor, both against the chemical action of the char eand against the intense heat. of

.the interlor of the furnacef In accordance with the present invention, a

coating of protective materials is applied to the face of the magnesite brick and caused to be impregnated therein. I This coating is gradually applied while the charge is being withdrawn from the furnace andwhile parts of the charge still adhere to the walls.

The invention also consists in certain new and original features of construction and combinations of parts hereinafter set forth and claimed.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of'its operation and the manner of its organization may be better understood by referring to the following description takenin connection with the accompanying drawings forming a part thereof; in which a Figure 1 is a sectional view of a conventional type of furnace, showing the lining applied thereto in accordance with the present invention;

Figure 2 is an enlarged detail view showing the lining and illustrating the bonding action between the lining and the walls; and

Figure 3 is an enlarged detail view showing the lining built up to a substantial thick- 50 ness.

Like reference characters denote like parts in the several fi res of the drawin s.

In the followm description an in the claims parts will names for convenience, but they are intended to be as generic in their application to-similar parts as the art will permit. I

Referring to the drawings more in detail, the invention is shown as applied to a furnace comprisin an arch 1 and a pair of side walls, 2 whic may be formed of any suitable material, as, for example -silica, or magnesite brick. Suitable doors, 3 areprovided through which the furnace. may be charged, and the working conditions thereof controlled. Base 4 may be formed of any suitable material, such as brick or burned-in quartz.

Inthe operation of a furnace of this type, in the refining of copper, a bath of molten copper is maintained at an elevation slightly below the bottom of doors 3 until the desired metallurgical reactions have taken place.

The charge is then tapped for subsequent treatment andthe operation repeated with a fresh charge.

It has been found that in furnaces operated as above the molten copper adheres to the walls and enters into the bricks themselves, which become impregnated to a. substantial depth. The copper becomes oxidized, due to the strongly" oxidizing conditions maintained in the furnace, and forms tenorite and cuprite. I

The present invention takes adv'anta e of the above mentioned copper coating an utilizes the same for forming a protective covering over the furnace walls. This is accomplished by forcing the finely divided silica against the furnace walls while the charge is being withdrawn. The silica adheres to the film of molten copper and becomes firmly embedded therein, while the heat of the furnace chan es substantial amounts of the silica to tri ymite, in which form it'i's stable between the temperatures of 870 and 1470? C.

The silica is sprayed, or otherwise thrown upon the walls just above the molten bath as the charge is withdrawn until substantially the entire surface of the wall has been cove identified by specific ered by the protective coating. The operation ides of copper and absorbed silica, said mais repeated for subsequent charges and the trix having silica particles embedded therein. coating 5 built up to the desired thickness In testimony whereof I have hereunto set due to the bonding action of the molten cop per. A homogeneous mass of the composition above mentioned is obtained, which may be made to cover the entire inner wall of the furnace and prevent the magnesite brick from becoming Worn. It has been found in practice that the life of a brick when used in a furnace wall, as above mentioned, is materially increased, thereby increasing the total time during which a furnace may be operated and decreasing the maintenance charge.

Although applicant is not aware of the exact nature of the changes undergone by the various elements in carrying on this process, it is believed to take place in two stages, namely the silicious material is firmly bonded to the magnesite brick and enters into the interior thereof, While successive layers or accumulations of this material are bonded upon the previous layers. This is thought to be accomplished by an assimilation of silica in the copper oxide with which the magnesite brick or the silica material is impregnated. Analysis of the furnace lining has revealed, however, that definite quantities of cuprite, tenorite, tridymite and quartz are present. The amount of metallic copper remaining is comparatively small,since under furnace conditions the above mentioned oxides have been formed. Because of the high temperature the quartz grains have been highly fractured and have been largely converted into tridymite.

It is obvious that a lining formed as above provides a strong protective coating for the furnace walls in the form of a single uniform mass. A copper refining furnace having a magnesite brick lining has been described for purposes of illustration. It is to be understood, however, that the invention is not limited thereto but may be applied to other furnaces and to other lining materials.

While certain novel features of the invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitu tions and changes in the forms and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. A furnace lining comprising silica particles bonded in a matrix of oxides of copper and absorbed silica.

2. A furnace lining comprising a porous refractory material im regnated with a mass of silica grains embed ed in. a matrix of oxides of copper and absorbed silica.

3. A furnace lining comprising a magnesitc brick impregnated with a matrix of OK- my hand.

GEORGE DAVID EVANS, 

